The beard trimmers of the state of the art have linear moving and fixed blades, the operation of which is based on a to-and-fro movement of the moving blade relative to the fixed blade. This type of trimmer is generally equipped with a comb that allows it to adjust the cutting length of the beard. Such beard trimmers are for example disclosed in US D 698,084, U.S. Pat. No. 6,978,547, US D 486,267, EP 2 766 153 A1, US D 363,809, US 2013/0042487, U.S. Pat. No. 7,076,878, US D 521,683, etc.
Of course, razors with multiple rotary heads exist that make it possible to achieve a very close shave, but they cannot be used to trim a beard. Razors do not have combs to adjust the distance between the cutting mechanism and the skin. To the best of our knowledge, no beard trimmer with rotary heads having a vertical axis exists in the state of the art.
The trimmers of the state of the art have a straight cutting line at the intersection of the moving teeth and fixed teeth. They have the drawback of trimming the hairs differently depending on the trimming direction, since the beard hairs are most often inclined in a direction, given that they almost never grow perpendicular to the skin. The result of trimming with these trimmers is thus very different depending on the movement direction over the beard to be trimmed.
Trimmers with cutting heads having a vertical axis comprising a protection position for the combs are not known in the state of the art.